Revert "Revert "Add color spin test for SkColorSpaceXformCanvas""

This reverts commit 73e21af21390c2806eb1350253233903808edd6b.

Reason for revert: I will fix the broken bot next week.

Original change's description:
> Revert "Add color spin test for SkColorSpaceXformCanvas"
> 
> This reverts commit cb01aec63bcb3dee52afcf3605bcd64166b873c0.
> 
> Reason for revert: Breaks Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Debug-SK_USE_DISCARDABLE_SCALEDIMAGECACHE
> 
> Original change's description:
> > Add color spin test for SkColorSpaceXformCanvas
> > 
> > Also changes behavior to treat nullptr srcs as sRGB.
> > 
> > Testing locally, it looks like 353 gms have no diffs from 8888.
> > There are 269 diffs - some are fine (gms that do color space stuff)
> > and some are bugs.
> > 
> > BUG=skia:
> > 
> > Change-Id: I55c2825f4f4b857e0b0a0ec050c6db82ac881492
> > Reviewed-on: https://skia-review.googlesource.com/9738
> > Reviewed-by: Brian Osman <brianosman@google.com>
> > Commit-Queue: Matt Sarett <msarett@google.com>
> > 
> 
> TBR=mtklein@google.com,msarett@google.com,brianosman@google.com,reviews@skia.org
> # Not skipping CQ checks because original CL landed > 1 day ago.
> BUG=skia:
> 
> Change-Id: I70bb69f747b863d267494e37a60888a51ab0184c
> Reviewed-on: https://skia-review.googlesource.com/9823
> Reviewed-by: Eric Boren <borenet@google.com>
> Commit-Queue: Eric Boren <borenet@google.com>
> 

TBR=borenet@google.com,mtklein@google.com,msarett@google.com,reviews@skia.org,brianosman@google.com
# Not skipping CQ checks because original CL landed > 1 day ago.
BUG=skia:

Change-Id: I766382e6655f614042cded84f547f9fd5b109fca
Reviewed-on: https://skia-review.googlesource.com/9879
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
diff --git a/dm/DM.cpp b/dm/DM.cpp
index 4b51030..d3d1239 100644
--- a/dm/DM.cpp
+++ b/dm/DM.cpp
@@ -14,6 +14,7 @@
 #include "SkCodec.h"
 #include "SkColorPriv.h"
 #include "SkColorSpace.h"
+#include "SkColorSpacePriv.h"
 #include "SkCommonFlags.h"
 #include "SkCommonFlagsConfig.h"
 #include "SkCommonFlagsPathRenderer.h"
@@ -895,9 +896,26 @@
                                  SkColorSpace::kAdobeRGB_Gamut);
 }
 
+static sk_sp<SkColorSpace> rgb_to_gbr() {
+    float gbr[9];
+    gbr[0] = gSRGB_toXYZD50[1];
+    gbr[1] = gSRGB_toXYZD50[2];
+    gbr[2] = gSRGB_toXYZD50[0];
+    gbr[3] = gSRGB_toXYZD50[4];
+    gbr[4] = gSRGB_toXYZD50[5];
+    gbr[5] = gSRGB_toXYZD50[3];
+    gbr[6] = gSRGB_toXYZD50[7];
+    gbr[7] = gSRGB_toXYZD50[8];
+    gbr[8] = gSRGB_toXYZD50[6];
+    SkMatrix44 toXYZD50(SkMatrix44::kUninitialized_Constructor);
+    toXYZD50.set3x3RowMajorf(gbr);
+    return SkColorSpace::MakeRGB(SkColorSpace::kSRGB_RenderTargetGamma, toXYZD50);
+}
+
 static Sink* create_via(const SkString& tag, Sink* wrapped) {
 #define VIA(t, via, ...) if (tag.equals(t)) { return new via(__VA_ARGS__); }
-    VIA("adobe",     ViaCSXform,           wrapped, adobe_rgb());
+    VIA("adobe",     ViaCSXform,           wrapped, adobe_rgb(), false);
+    VIA("gbr",       ViaCSXform,           wrapped, rgb_to_gbr(), true);
     VIA("lite",      ViaLite,              wrapped);
     VIA("pipe",      ViaPipe,              wrapped);
     VIA("twice",     ViaTwice,             wrapped);
diff --git a/dm/DMSrcSink.cpp b/dm/DMSrcSink.cpp
index 4f5cd43..14d5552 100644
--- a/dm/DMSrcSink.cpp
+++ b/dm/DMSrcSink.cpp
@@ -1842,13 +1842,41 @@
 
 /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
 
-ViaCSXform::ViaCSXform(Sink* sink, sk_sp<SkColorSpace> cs) : Via(sink), fCS(std::move(cs)) {}
+ViaCSXform::ViaCSXform(Sink* sink, sk_sp<SkColorSpace> cs, bool colorSpin)
+    : Via(sink)
+    , fCS(std::move(cs))
+    , fColorSpin(colorSpin) {}
 
 Error ViaCSXform::draw(const Src& src, SkBitmap* bitmap, SkWStream* stream, SkString* log) const {
     return draw_to_canvas(fSink.get(), bitmap, stream, log, src.size(),
                           [&](SkCanvas* canvas) -> Error {
         auto proxy = SkCreateColorSpaceXformCanvas(canvas, fCS);
-        return src.draw(proxy.get());
+        Error err = src.draw(proxy.get());
+        if (!err.isEmpty()) {
+            return err;
+        }
+
+        // Undo the color spin, so we can look at the pixels in Gold.
+        if (fColorSpin) {
+            SkBitmap pixels;
+            pixels.allocPixels(canvas->imageInfo());
+            canvas->readPixels(&pixels, 0, 0);
+            for (int y = 0; y < pixels.height(); y++) {
+                for (int x = 0; x < pixels.width(); x++) {
+                    uint32_t pixel = *pixels.getAddr32(x, y);
+                    uint8_t r = SkGetPackedR32(pixel);
+                    uint8_t g = SkGetPackedG32(pixel);
+                    uint8_t b = SkGetPackedB32(pixel);
+                    uint8_t a = SkGetPackedA32(pixel);
+                    *pixels.getAddr32(x, y) =
+                            SkSwizzle_RGBA_to_PMColor(b << 0 | r << 8 | g << 16 | a << 24);
+                }
+            }
+
+            canvas->writePixels(pixels, 0, 0);
+        }
+
+        return "";
     });
 }
 
diff --git a/dm/DMSrcSink.h b/dm/DMSrcSink.h
index c973e3b..b6e1b59 100644
--- a/dm/DMSrcSink.h
+++ b/dm/DMSrcSink.h
@@ -496,10 +496,11 @@
 
 class ViaCSXform : public Via {
 public:
-    explicit ViaCSXform(Sink*, sk_sp<SkColorSpace>);
+    explicit ViaCSXform(Sink*, sk_sp<SkColorSpace>, bool colorSpin);
     Error draw(const Src&, SkBitmap*, SkWStream*, SkString*) const override;
 private:
     sk_sp<SkColorSpace> fCS;
+    bool                fColorSpin;
 };
 
 }  // namespace DM